At least since Noah, and likely long before, we've stared in horror at catastrophe and tried to suss out deeper meaning – it was but weeks ago that the Tokyo governor, Shintaro Ishihara, declared that the earthquake/tsunami/ reactor tripleheader was "divine punishment" for excess consumerism. This line of reasoning usually fails to persuade these days (why are Las Vegas and Dubai unscathed by anything except the housing meltdown?) but it's persistent. We need some explanation for why our stable world is suddenly cracked in half or under water. Still, over time we've become less superstitious, since science can explain these cataclysms. Angry gods or plate tectonics? We're definitely moving towards natural explanation of crises.

Which is odd, because the physical world is moving in the other direction.

The Holocene – the 10,000 years through which we have just come – was by all accounts a period of calm and stability on Earth. Temperatures and sea levels were relatively stable. Hence it was an excellent time to build a civilisation, especially the modern kind that comes with lots of stuff: roads, buildings, container ports, nuclear reactors. Yes, we had disasters throughout those millennia, some of them (Krakatoa, say) simply enormous. Hurricanes blew, earthquakes rocked. But they were, by definition, rare, taking us by surprise – freaks, outliers, traumas that persisted in our collective history precisely because they were so unusual.

We're now moving into a new geological epoch, one scientists are calling the Anthropocene – a world remade by man, most obvious in his emissions of carbon dioxide. That CO2 traps heat near the planet that would otherwise have radiated back to space – there is, simply, more energy in our atmosphere than there used to be. And that energy expresses itself in many ways: ice melts, water heats, clouds gather. 2010 was the warmest year on record, and according to insurers – the people we task with totting up disasters – it demonstrated the unprecedented mayhem this new heat causes. Global warming was "the only plausible explanation", the giant reinsurer Munich Re explained in December, of 2010's catastrophes, the drought, heatwave and fires across Russia, and the mega-floods in Pakistan, Australia, Brazil and elsewhere were at least plausibly connected to the general heating. They were, that is to say, not precisely "natural disasters", but something more complex; the human thumb was on the scale.

We still have plenty of purely natural disasters – though scientists can posit reasons climate change might make the world more seismically active, tectonic and volcanic forces seem beyond our reach; the great wave that broke over Sendai really did come out of the blue. But even in Japan, of course, the disaster was not entirely "natural". The subsequent fallout was… fallout, the invisible plume streaming from one of our highest-tech marvels, a complex reduced in minutes into something almost elemental, a kind of utility-owned volcano.

In a sense Ishihara was correct when he decried "selfish greed". It is consumerism that has flooded the atmosphere with CO2: the constant getting and spending, where $1 spent liberates roughly 1lb of carbon. We are remaking the world, and quickly; we are stumbling into a new way of thinking about disaster, where neither God nor nature, but man is to blame.

That changes the valence of catastrophe. Since warm air holds more water vapour than cold, the atmosphere is nearly 5% moister than it was just a few decades ago. That loads the dice for great floods of the kind suddenly so common. I lived through one in my small mountain town in Vermont two summers ago: the biggest thunderstorm in our history dropped buckets of rain in a matter of hours. Our town is almost entirely intact forest; it should have been able to hold whatever nature threw at it. But that rain fell on a different planet from the one the forest had grown up on; every road washed out, and the governor had to visit by helicopter. But at least we had the solace (or self-lacerating realisation) that we'd helped cause this deep change. Americans burn more carbon per capita than just about anyone; what do you say to a Pakistani farmer watching the swollen Indus wash away his life's work? And since global warming seems to take first aim at the poorest places that have done the least to cause it, this is a question we may be asking ourselves a good deal in the decades to come.

Not every natural disaster is unnatural now, and we may be able to fool ourselves a little longer. But these days it's the climate deniers who act like the pious of yore, unable to accept the truth. I was surprised, and impressed, to read a poll of Americans taken recently. By healthy majorities, this most religious of western citizenries said natural disasters were more likely to be a sign of climate change than of God's displeasure.

Which is good news, because for the first time in human history we can prevent a great deal of unnecessary cataclysm in the years ahead. Not all of it – there will always be earthquakes and hurricanes. But every bit of carbon we keep out of the atmosphere is that much less extra energy we add to the system. It's that much less disaster waiting to happen.

Japan earthquake

March: Earthquake of magnitude 9.0 off the north-east coast of Japan, followed by a 15-20m high tsunami Human cost: More than 10,000 dead; 17,000 missing Economic cost: £189bn Survivor's story: Taiko Sawadate, 59, nurse, Otsuchi CityWhen the alarms rang, I had about 20 minutes to evacuate with my mother. We drove even higher than the recommended safe area, so I was sure it was OK. Someone shouted, "It's coming" and I got out to have a look. The waters were upon us. I just about got my mother out of the car, but she tripped over. As I reached out to grab her, the tsunami swept us away. I was sure I was going to die.

It was dark in the water and I was being hit by debris on all sides. At one point, I saw an entire house coming towards me. But the surge forced me forward and suddenly up into the air and on to a slope. At last I could breathe. I really don't know how long I was in the tsunami. The whole thing probably lasted less than a minute.

Some people found me and gave me dry clothes. I dressed my own wounds. About 20 of us evacuated to a house high on one of the slopes. We found six bodies that first day and more on the second, including my mother's. It wasn't far. I wrapped it in the cleanest sheet I could find and put a stone border around it. Then I covered it with a futon, so the crows could not get at it. I said a prayer and left her there. There are so many bodies, the authorities are not sure what to do with them all.

On the second day, a fire broke out on the mountain, and we didn't have much food – just one piece of bread or one rice ball each for the day.

On the third day, the winds turned bitterly cold, so we walked for an hour to a public shelter at a school. When we arrived at Otsuchi, the city was still burning.

I have nothing left. My savings, bank book and ID cards are all washed away.

Eventually I want to move away from the coast. I feel bad about that, as my family have been here for more than five generations. But I'm too frightened to stay.Jonathan Watts

Brazilian landslide

January: Torrential rainstorms trigger mudslides in the mountainous Serrana region outside Rio de Janeiro, the worst natural disaster in the country's history. Human cost: 916 dead; 345 missing Economic cost £187mSurvivor's story: Mauricio Berlim, 35, undertaker, TeresopolisOnly the following day did the scale of the disaster become clear. The first family came in at about 2pm – they had lost four relatives, three adults and one child. By 10pm, I was organising 50 burials.

That night, cars and vans started turning up at the city morgue with bodies inside. I stayed until 4am – the bodies never stopped arriving, there were so many desperate families trying to identify their relatives. It was madness. People couldn't find their relatives because the bodies were so dirty. It was terrible.

After two days we ran out of coffins. On the Friday I called our supplier and ordered more; we got through 175. Because there were so many dead, they moved the morgue into an old church. The bodies were laid out on long tables covered in black plastic sheets. We started using a truck instead of hearses to transport the bodies to the funeral parlour. Instead of taking one body at a time, we would take 10 or 15.

Until 20 days ago there were still bodies inside the church. Now I think there are none left. The problem now is death certificates – none has been issued yet. Many people are still missing.

Thank God, nobody in my family was killed. I have one friend who had to leave his house, because there was no water or electricity, but that was all.

The city is returning to normal, but there was no carnival this year. Every week there are protests, demanding the impeachment of the mayor. Things are confused. Many people still have nowhere to live.

In front of my office you can see one of the mountains that collapsed; one report said boulders came crashing down at 180km an hour.

My family has been in the funeral business for 106 years and no one had ever seen anything like it.Tom Phillips

Australian floods

November 2010-January 2011: Queensland and Victoria floodsHuman cost: 37 dead, nine missing Economic cost: £19bn – Australia's costliest natural disaster everSurvivor's story: Ashley Hay, 40, novelist, BrisbaneThe silence was vast. There were no birds singing, no cars on the roads. The only sound was the tiniest turn of water retreating across our lawn. I had left home three days earlier, on a wet day, but a normal one, and came back to find my house a little yellow island jutting out of a wide brown sea.

Two days before, our suburb had been in a frenzy. My husband reported belongings being crammed into vans, trucks, cars – anything that would hold them. The traffic jammed as it tried to get to anywhere but here. Our grass, he said, was busy with flightless insects trying to get to higher ground: leeches, cockroaches, spiders. And it rained and it rained.

We knew how high the water had crept in Brisbane's infamous 1974 flood. There were predictions of an extra metre this time. My husband took our son, some stuff, left most of what we owned, and went away.

Now, seeing our street, it was shocking. The Brisbane river had breached its banks, spilling across roads and parks, over cars and trees, to mark out a new shoreline, here, in our front garden. It was quiet and still and, the strangest thing of all, the sun was blazing down. The rain had stopped. The flood had peaked at 4.46m, a metre below the 1974 mark.

It was 13 January, and the water was ebbing towards the day's first low. Suddenly, we knew the times and heights of the tides; suddenly we were attuned to its six-and-a-half-hour rhythm. Suddenly we were seafarers, watching our neighbours launch a boat from their drive. When the water drained away – it had gone by the next day – everything that had been immersed was a strange monochrome, halfway between brown and grey, fetid and slippy.

And then it began. Taking every single thing out, piece by piece, to decide if it could be saved. It was unreasonably exhausting. We washed; we dried; we papered the lawn. And after a few days, we threw it all away. Who cares about a notebook that stinks like a sewer? Who needs a Christmas decoration that drips dark muck from hidden crevices, no matter how many times you rinse it, shake it out, pat it dry?

Around us, houses were stripped and gutted – kitchens and bathrooms reduced to soggy piles of chipboard. A third of Brisbane's annual landfill – more than 110,000 tonnes of rubbish – was dumped in a week.

The floods were almost three months ago now, and it's still too quiet. We're still the only people back on our strip. We tell ourselves we're the luckiest people around.Ashley Hay's first novel, The Body In The Clouds, was shortlisted for the Commonwealth Writers' Prize.

February: Earthquake of magnitude 6.3 hit the city of ChristchurchHuman cost: 166 deadEconomic cost: £4.5bn-£6.75bnSurvivor's story: Anne Malcolm, 71, counsellor, ChristchurchI don't normally work on a Tuesday, but our counselling agency had a meeting from noon to 1pm [on the fifth floor of the Canterbury TV building]. The meeting was drawing to a close when, with no warning, the room exploded. Everything began to fly in all directions.

There had been aftershocks from the earthquake in September – we were used to the building wobbling. This was different. The explosion was sharp, jagged. Massive. I remember this sound of the structure breaking. The next thing I recall was being completely buried. I had very, very heavy masonry and beams on me.

Our floor, the top floor, came right down. There were 10 of us in the room and some rode down on the descending wall, almost surfed down with the building. Somehow the shock and adrenaline seemed to protect me, so in those first moments I didn't experience intense pain. I felt safe. I felt I would survive.

Two young policemen arrived within seconds. They clambered on to the rubble and began digging. Soon after, I was in the ambulance. I had surgery, and now I'm in a rehabilitation unit. I have only one functioning limb. I guess I'm here for at least another three to four weeks, until I can begin using these limbs again.

In hospital, I'm on the ground floor. I can't imagine going into a building that's more than one level. When the aftershocks come, my heart rate increases, but then a staff member arrives to see how you are. How I'll be when I get home, I don't know.

My local supermarket has gone, my post office has gone, my bakery has gone – everything that was part of my village life is gone.

Our much-loved computer whiz-kid, who had been with us for 10 years, died on our floor. But on every other floor in that building, it's the other way around – one or two people were rescued, but everyone else was lost. We were the fortunate ones.Toby Manhire

Sri Lankan floods

January-February: Devastating floods hit the country; more rain fell in Batticaloa than it normally gets in a yearHuman cost: 62 dead; 1.1 million displacedEconomic cost: £300mSurvivor's story: Milvahanam Loganadan, 40, driver, BatticalaoIt was about 7.30pm and we were sitting down to watch TV when we heard people making a lot of noise in the street outside. "The water is coming," they were shouting. "It's a flood."

I didn't know what to do – we have a seven-month-old baby and a four-year-old. But even before I could get to the door, the water was coming into the house. It was rushing in, so we picked up the children, ran out and kept going until we got to higher ground.

I convinced a rickshaw driver to take the rest of my family to my wife's mother's house, which is on top of a hill. It was chaotic. There had been no warning on the television or radio, so it was totally unexpected. It had been raining, certainly, but not enough for us to think that a flood was on its way.

Once my family were safe, I went back to the house to get valuables and documents. Everything else was ruined. I checked on the neighbours. The navy and police had got to our street with boats to evacuate the ones who couldn't move themselves.

Most people moved in with relatives, but quite a lot of people ended up in camps for the displaced. Happily, there were no deaths among my friends and family, although I know other people did die. There were snakes in the water; that killed a few, I heard.

We spent a week cleaning the house and then the waters came again and we had to evacuate again, and then clean it up once more. All our furniture has gone, and my motorbike, but it could have been worse. I've got a job, which helps a lot. Most of the farmers have lost a lot of their crop and other people needed the dry rations the NGOs were handing out to stay alive.

It is the fear that is the toughest thing to deal with. The children were really frightened when it happened and Laksher, my four-year-old, is still scared that the waters will come again in the middle of the night.Jason Burke

March: Magnitude 6.8 earthquake struck about 30 miles north of Tachileik on the Thai-Burma border Human cost: At least 75 dead; more than 110 injuredEconomic cost: Not yet knownSurvivor's story: Sai Noom Khan (not his real name), 23, TachileikI was with my wife watching television when a loud knocking started suddenly. The room started to shake and all our photos fell off the wall. It was terrifying. I had never experienced an earthquake before.

I was worried the house would collapse, so I grabbed my wife by the hand and we ran. We ran outside, but the ground was shaking so much it was hard to stand up. It lasted only about 40 to 50 seconds.

We live on the top of the mountain, so there wasn't too much damage. Since the earthquake, everyone's been sleeping outside. It's cold, but we're too scared to sleep indoors.

Yesterday I visited the villages of Tarlay and Mong Lin, about 30 miles away. They were devastated. I was told more than 100 people died there.

January-March: Heavy rains continued from December last yearHuman cost: At least 75 deadEconomic cost: £27mSurvivor's story: Ray Calleja, 43, hospital porter, Leyte ProvinceWe lost everything. It was the morning of 17 March. I watched, helpless, as our home was taken away by the floods. The only reminder that our house stood there was a lonely post. This was the first time I've seen the waters that high. I'm 5ft 5in and the floodwaters could have easily swallowed me. My wife and I saved every peso so we could buy the things we need. But we couldn't take anything. We had to save ourselves. How will I have a house again? I'm 43, I earn P6,000 (£86) a month. That house cost us P30,000 (£430). When I saw everything we worked for all these years had disappeared, I cried.Purple S Romero

January: Severe storms, lightning and floodsHuman cost: 91 dead, 321 injuredEconomic cost: £73mSurvivor's story: Amos Ndlovu, 47, unemployed painter, Diepsloot Township, JohannesburgI've lived here for 10 years and this is the worst flooding I've known. There was heavy rain and I was afraid because I didn't even know where to put my kids. We couldn't open the front door because more water would come in, and it wasn't even safe to open the window.

We wanted to stay inside, but we could see the water was a metre high, so we used a hatch to climb on the roof – we waited there for four or five hours. It was raining hard. We couldn't run away because we had to look after our property.

That day was a disaster. Everything was washed away. Before the flood, we had power in the house, but now there is no electricity. Until they fix it, there's nothing we can do.

We are using candlelight and it will be cold in winter. I felt very sad. The most precious thing I lost was my car. It was stuck in mud and filled with water, and now it won't start. I'm not working at the moment and I don't have money, so I can't fix it.

It's nobody's fault, but I'm worried that it might happen again. The local government could do more to protect us. The system here is badly designed. If you build homes here, you must make a way for the water to run.David Smith